Tag: Simulation

It took nine months to reproduce our galaxy, but it was well worth the effort! Researchers at the University of California, Santa Cruz and the Institute for Theoretical Physics in Zurich created this stunning reconstruction of the Milky Way galaxy by running a simulation on a supercomputer for nine long months. The result is not only beautiful, but also significant in scientific terms. And just for the records, this is the first time such a simulation has been achieved!

The Eris Simulation (Courtesy: UC Santa Barbara)

There have been many previous attempts. Every one of them resulted in failure, usually ending up with a huge central bulge. Javiera Guedes, the first author of the paper on the simulation, says it better:

Previous efforts to form a massive disk galaxy like the Milky Way had failed, because the simulated galaxies ended up with huge central bulges compared to the size of the disk

The paper has ben submitted to the Astrophysical Journal and has been accepted for publication. The simulation is remarkably close to the Milky Way. The authors call their simulation Eris’. Take a look as to how close it is to the actual thing in the picture below:

Comparison between the Eris simulation and the Milky Way Galaxy

Cold Dark Matter

The model simulation is important for the support it lends to the ‘cold dark mattertheory of cosmology. Dark matter is a hypothesis used to explain the rotation of galaxies amongst many other things like Cosmic Microwave Background Radiation. The amount of matter we see in the galaxy cannot provide enough gravitation to hold the spinning galaxy together, so scientists postulated the presence of another type of matter one which does not interact with other matter at all, but provides the necessary gravitational pull. Since, it doesn’t interact and cannot be seen’, it is called Dark Matter. There are many models for Dark Matter too. One of them involves particles moving at low speeds, or are cold’.

The key to the success of this team, where many previous attempts have failed, has been the correct simulation of the star formation process in real galaxies. Star formation happens in gas clouds in clumps in the galactic region. These pockets are supported by Dark Matter. Dark Matter halos create gravitational wells, or regions where the gravitational potential is low. These are the regions that matter can reside in and are the hotbeds of gas clouds.

What took nine months?

The remarkable success of the team was the amazing resolution they could achieve. Resolution means tracking several stars and simulating their interactions with each other, both extremely tough jobs. NASA’s Pleiades supercomputer and other supercomputers at UC Santa Barbara and the Swiss National Supercomputing Centre came to the rescue, but together they took nine months to process the data.

Simulations are always satisfying since they assure us that what we know is not wrong. This one is a strong case in point.